Kirn is a surname. Notable people with the surname include:

  • Hans Kirn (1920–2007), German Luftwaffe pilot
  • Louis Joseph Kirn, United States Navy admiral
  • Otto Kirn (1857–1911), German theologian
  • Roman Kirn, Permanent Representative of Slovenia to the United Nations
  • Walter Kirn, American novelist and critic
  • Peter Kirn, Melbourne Drifter
  • Ivana Kirn, Melbourne License Suspendee & Vampire